There are indeed few tires available in ETRTO 355.

Besides the Schwalbe, there are also Panaracer Minits Lite PT in ETRTO 355 but they are very difficult to find outside Japan.

There are also some BMX tires in ETRTO 355 most of there are very wide tires (more than 50mm wide and won't fit on the Birdy I think).

I changed my wheels for ETRTO 349 (Brompton wheel size) that is only 6mm smaller because there are now much more tires available in ETRTO 349 than in ETRTO 355.

IMHO, for the typical use of the Birdy as a high quality, convenient folding city bike, the Marathon can't be beat. It has great durability and puncture protection, and has width enough to be safe on bad pavement and gravel. It's also good for touring, for the same reasons. So for that purpose, 355 is fine. For racing / fast training, offroad, or other specialty use (for a folding bike), 355 or 406 gives more choice, and cheaper tires. For racing 28-406 is ca 2 cm larger in diameter than 44-355, as is a balloon 55-349, if that exists. A 349 much narrower than 50 mm would be smaller than the 44-355.

Before moving to ETRTO 349, I considered the ETRTO 406 option and tried to mount ETRTO 406 wheels equipped with Schwalbe Pro-one 28x406 tires.

It wasn't possible to install the ETRTO 406 front wheel with the mudguard in place. I had to remove the front mudguard.

It is of course impossible to mount ETRTO 406 wheels with tires wider than 28mm.

This was for me a too big limitation because there aren't many tires in 28x406 and all are high pressure road tires.

The maximum wheel diameter with the front mudguard is really the Big Apple 50x355. This tire rides well but its puncture protection isn't very good and there are no Big Apple Plus or Big Ben Plus (balloon tire with very good puncture protection).

In ETRTO 349, there is the very puncture resistant Marathon Plus, there is the Marathon green guard, the fast Schwalbe One, the in-between Marathon Racer (now also in folding), the new Conti Contact Urban, the very fast Greenspeed Scorcher 120 and more protected Scorcher Kevlar in 40x349, the Josef Kuosac tires, the Velotto phantom... so many different types of tires (forget the bad Kojak). There is no balloon tire but for me this isn't needed with the excellent full suspension of the Birdy.

Converting Birdy GT to 20"
 

Hi all , I apologize if this topic had been discussed before. But I just wonder if I can change/converting my 18" birdy GT 2019 wheels into 20" wheelset?
If anyone did that before and can give me good advice, I will be very thank you and much appreciated .
have a good weekend

To convert into 20" wheels ETRTO 406 (there is another 20" size = ETRTO 451 that won't fit on the Birdy), you need to rebuild your wheels = keep the hubs and replace rims+spokes+ tires.

If you want to keep your original 18" ETRTO 355 wheels, you need to also buy hubs.
The rear hub is a standard 135mm wide quick release 5mm hub.
But the disc front hub is specific for the Birdy, you cannot use any standard 100mm wide hub because the disk won't be at the good position (the front disc of the Birdy is not only on the right side of the bike instead of the left side as usual but its distance from the center of the wheel is also different). There is a special Birdy disc from Hubsmith, there is also a special Birdy disc Shutter Precision dynamo hub.

As I already explained above, there is a limitation in tire width when using ETRTO 406 wheels = max width is 28mm meaning that there aren't so many tires available (Schwalbe Pro-one and One, some Continental tires, note that with the rims I tried, the Pro-one were wider than 28mm and too wide to fit on the Birdy with front mudguard). All these 28mm wide ETRTO tires are road high pressure tires.

Is that true of the front hub of the Mk3 as well? I thought it was a standard SunRace hub to match the Capreo compatible rear?

The special hub is needed for all Birdy with front disc brake on the right side of the fork.

Rim brakes Birdy use a standard OLD 100mm front hub.

Nowadays, Riese & Müller mount a Shutter Precision hub dynamo. Previously, there was a SON hub dynamo for Birdy disc but as far as I know, it is discontinued (not on the website of SON Nabendynamo anymore).

As said, the front hub has a standard 100mm OLD. The problem is that the disc isn't placed at the same distance from the fork side (and of the center of the wheel) as with a standard 100mm OLD front disc hub, so a standard 100mm OLD front hub flipped to put the disc on the right side won't fit.

Thank you very much for your response/answer. It's clear that we can convert it to 20" 406.

Yes, it is, as long as you use narrow, 28mm max wide, tires.

Awesome!

Pacific Cycles has a new online shop allowing to shop from almost everywhere in the world ??
Pacific Cycles online store

Nice! I like the blue and tangerine frame colours, I haven't seen those before. Interesting also that all Pacific Birdys seem to have mechanical brakes, no hydraulics, unlike R & M. And there are no internal gear hubs apart from the Rohloff.

I'm looking for stiffer suspension for my weight and touring load. Swapping the default red elastomer for a green one is easy, and I think that's the most important change for my needs anyway. For the front there are two different springs available. The one I have (8.5 coils) seems to be the stiffest one, since the 10.5 coils is of thinner material.
https://store.pacific-cycles.com/Pro...095&p=2&page=5
https://store.pacific-cycles.com/Pro...093&p=2&page=5

Then there is the much more expensive "U Design" suspension set, which is more fancy looking than the originals, but still elastomer based. Does anyone know how they compare in stiffness and travel?
https://store.pacific-cycles.com/Pro...104&p=2&page=5

Belt drive Birdy?
 

Conventional wisdom says you can't use a drive belt on full suspension bikes with variable chainstay length, because the belt needs high tension and can't be bent backwards. The R & M Delite seems to disprove this:
https://cimg8.ibsrv.net/gimg/bikefor...701844a027.jpg
R & M Super Delite

It uses a seemingly flexible belt tensioner:

https://cimg0.ibsrv.net/gimg/bikefor...cf08121533.jpg
Belt tensioner

I have Gates belt drive on another bike, and I'm really happy with it. Zero maintenance, no dirt, no noise, and long life (10.000 km so far, and no sign of wear). So I'm wondering if it might be doable to convert a Birdy to belt drive. Obviously we'd need ring and sprocket in suitable sizes, and a belt of suitable length. Then a tensioner, and finally a way to handle the belt when folding. However the bottom bracket chain manager on current Birdys looks like it could handle a belt just as well. We'd need to ensure the belt stays clear of the finicky chainstay of the Birdy, too. Maybe a project for next winter.

Currently I'm using a wax-based chain lube on my Birdy, this reduces the dirt but increases the noise, and requires very frequent lubing. There are some who don't see any benefit in belts and I respect that, but for me the benefit is very clear, having tried it. Of course if you prefer cassette gears, you can forget about belts.

Kinetics has made belt drive Brompton's.

But it seems more difficult for the Birdy because to fold the bike the chain must be on the smallest sprocket and belt drive sprockets are bigger than chain sprocket what could cause problems to fold the bike.

Another issue is folding the belt on the opposite side of the teeth what for many belts isn't allowed by the manufacturer.

For the Birdy suspension I have Multi-S suspensions (front and rear) the front Multi-S is real shock with a spring + an oil damper and adjustable spring pre-load.

https://cimg2.ibsrv.net/gimg/bikefor...7d85d9dbd2.jpg

This is not an issue, I think. The fold works well enough on middle sprockets, and I don't think it's about sprocket size, really. It's more about sprocket position, the outermost sprocket gives least trouble when folding.

Yes, but apparently it's fine for Gates CDX, which the Delite uses. You can see it bends the belt backwards over a quite small tensioner wheel.

I had a look at the sprockets now. The smallest Shimano IHG compatible Gates sprocket is 22t, that means 52t up front for my gearing. The closest Gates offers is 50 and 55t which is close enough. Belt pitch is 11 mm, vs. 12.7 mm for chains, so the sprockets are a bit smaller for the same tooth count, though they are wider. If there are no chainstay problems or belt length issues, the main challenge is making a suitable belt tensioner, which gives enough tension while not blocking the fold, and ideally keeping tension during the fold.

Interesting. That probably costs quite a bit too, but you're happy with it? For now I've ordered a green elastomer for the rear, and then I'll see if that is enough.

Yes, the Multo-S suspension works fine.

Cost about 170USD for front+rear when bought from Multi-S.

For touring??
 

Hi all, if I want to do a light touring, about 200km. Should I change the wheelset into 406 or let it be 355? Because I read that if I convert it into 406 then I only can put skinny tire on it 20x1.125 where they said will be harsh ride in bad road. While if I stick to 355 then I can put Big Apple on it where it will be much more comfort in long distance ride.
Thank you brothers

Hi! This depends on what you prefer and what kind of roads you will tour on. I toured on 44-355 Marathon tyres. They have good puncture protection and work well on gravel and bad roads. Big Apple has even better suspension, and 28-406 tires may be faster on paved roads. (They say if you choose 406, you cannot go wider than 28 mm.)

thank you for your sharing Glye... So in your opinion it will be better to stick to 355? My road will be a combination between good hotmix asphalt and bad road. My concern is that I prefer to cycling faster rather than comfort but slow. But then, if I am not comfortable then I also can't be fast. Any share experience on light touring with birdy will be much appreciated. Thank you

I am happy with 355, but some other people are happy with 406. People are different... I toured 770 km with medium/heavy luggage (big rear racktop bag, two small front panniers, front handlebar bag, staying in hotels). Picture at https://www.flickr.com/photos/gunnst...7710551162926/
Maybe try the first Birdy tour with the wheels you have, and then if you're not happy then you can switch to 406 before your next tour?

That's really wise advice. Thank you very much. Nice birdy with great pannier.
For 700 km... How many days you spent for the whole trip? Do you have a record how fast were you in average speed

Thank you

I'm not sure, but I think it was mostly less than 80 km per day, and average speeds less than 20 km/h. I am faster on my recumbent :D

I have a GT with the 1.9" Blackjack tires and see no need to change for speed. I average 21kmh on my smooth track rides with a max size 58t chainring and the only reason I can't go faster is the gearing and bad aero ergonomics. I can get up to 34kmh before gearing runs out, but I think aero is the problem above 28kmh, not the bike. The tires make noise but roll fast at the max pressure rating. 406 tires will allow higher speeds but will be more dangerous on bad roads.

The Birdy has good front and rear suspensions.

It remain comfortable even with high pressure narrow tires.

The problem is that there are no fast tires in ETRTO 355.

That's subjective, and depends on local road conditions. Good for you if that's enough for you, but some need more. The suspension travel is very short, and I wouldn't call it "comfortable" even with 44-355, but it's acceptable for me. There's also the safety aspect, wider tyres are safer with regards to cracks, holes, road debris, gravel-on-pavement, etc. Then there is the need for mudguards for practical riding, I don't know if 406 is possible with that.

This is the message anyone pondering 355 vs 406 should get: It depends on the rider and the road.